The present invention relates to a decorative film for glass-paned window and, more particularly, to a decorative film for glass-paned window, which is particularly superior in privacy protection, light screening property and decorative effect. The decorative film of the present invention can exert the excellent effect when applying to transparent glass-paned windows of structures such as house and building, and transparent glass-paned windows of vehicles such as car and train.
For the purpose of protecting privacy and screening light, it has widely been performed to coat a transparent glass-paned window with a special polarizing film through which the-situation inside the room or vehicle can not be observed easily, heretofore. The polarizing film to be applied to the glass-paned window includes, for example, film obtained by coating a transparent substrate such as polyester film and polyolefin film with ink containing powders of a metal such as aluminum, titanium and nickel; metallic film obtained by laminating a metal such as aluminum, titanium and nickel on a substrate such as polyolefin film; and film obtained by coating a substrate with ink having high screening property. Regarding such a polarizing film, when the scene inside is observed from the outside through the glass-paned window to which the polarizing film is applied, the glass-paned window of a gray or similar halftone color can be seen, merely, but the situation inside can not be observed. This is because only a brightness of the outside of the glass-paned window is reflected by a polarizing function of the film. Inside of the glass-paned window, the outside scene can be seen similar to the case where the polarizing film is not used, and the view is not obstructed.
The polarizing film of the prior art is useful for protecting privacy and screening light, as described above. However, as explained previously, the color observed from the outside, when using prior polarizing film, is black or gray, or a similar halftone color. Therefore, still some room for improvement in appearance is left.
Although its purpose is not directed to improve the appearance of the polarizing film itself, Japanese Unexamined Patent Publication (Kokai) No. 3-69397 discloses a decorative screen capable of performing different displays at both sides of a transparent door, a window and a partition in the room without obstructing see-through and light screening properties. As schematically shown in FIG. 1, this decorative screen has such a construction that a printing layer 24 having a lot of through-holes 25 is provided on a substrate 20 made of a transparent plastic or glass and the printing layer 24 has respectively a surface pattern layer 21 and a back surface pattern layer 23 via a screen ink layer 22 interposed between both pattern layers. This decorative screen can be produced by making a transfer sheet having the printing layer 24, forming a lot of through-holes 25, and transferring the transfer sheet on one surface of a substrate. For example, when this decorative sheet is applied to the glass-paned window, it is possible to see the opposite side through a lot of through-pores 25 formed on the printing layer 24 from any side, and to see a different pattern from each side. Therefore, it can be used for the purpose of advertising and decorating. However, in case of this decorative screen, it is necessary to make a transfer sheet as its precursor and, therefore, the production becomes complicated and an increase in cost is not avoided. Furthermore, the printed pattern is unattractive because it depends on a normal printed technique, and a fine pattern can not be printed.
Furthermore, Japanese Utility Model Registration No. 3041191 discloses a removable sheet-like advertising display capable of displaying advertising contents at the window portion of the side of transfer vehicles bodies such as car and train without obstructing the view. As shown in FIG. 2, since an advertising display 31 is applied to the portion including a portion of a window 35 of the side of a transfer vehicle body via an adhesive portion 34, the advertising display has through-holes 32 penetrating the sheet on the whole surface and, at the same time, an advertising display portion (a portion of the English letter is shown in the drawing) 33 is provided on the surface. The through-holes 32 are provided with enough size and distance so that the pattern of the advertising display portion 33 can be clearly confirmed from the outside of the vehicle body and, at the same time, the-scene of the outside can be seen from the interior of the vehicle body to some extent. However, in case of this advertising display, since a main portion of the sheet is occupied by the through-holes, the amount of an adhesive to be applied to the adhesive portion of the back surface becomes small and a sufficiently strong adhesive force can not be obtained. Furthermore, there is also a problem that, while the advertising display is applied to the glass-paned window, dust accumulates on the portion of the through-holes and the portion of the adhesive squeezed out by a pressing force at the time of applying the sheet, thereby to lower the adhesive force and durability. Although it is not disclosed in the specification, it is understood that the advertising display is produced by using the transfer method and perforating method in combination, similar to the decorative screen described previously with reference to FIG. 1. Accordingly, the production becomes complicated and there is a fear of causing such additional problems that an increase in cost is not avoided an a fine pattern can not be printed.
An object of the present invention is to solve one or more of the above problems of a decorative film for glass-paned windows of the prior art.
An additional object of the present invention is to provide a decorative film for glass-paned windows that is superior in at least one of its privacy protection, light screening property and decorative effect.
Another object of the present invention is to provide a decorative film for glass-paned windows that can be easily produced, has a sufficient adhesive force to the glass-paned window, and/or affords an attractive fine decorative pattern.
In accordance with one aspect of the present invention, a decorative film is provided that comprises a transparent substrate and a colored layer, where the colored layer comprises ink containing an optical coherent pigment. The colored layer is provided on one surface of the substrate.
According to one preferred embodiment, the decorative film of the present invention comprises a transparent substrate as well as a colored layer and a clear layer, which are laminated, in order, on one surface of the transparent substrate. An adhesive layer is provided on the surface of the substrate opposite the colored layer. The adhesive layer can be colored, but does not have to be, and the surface of the adhesive is preferably protected with a release liner such as release paper.
The decorative film of the present invention may also be used in the form of a modification of the above construction, according to the use and other factors. The decorative film of the present invention may have the other additional layer, in addition to the substrate and colored layer which are essential to the construction, and adhesive layer and clear layer which are preferably used. The respective layers may usually be used in the form of a single-layer, but may also be used as a multi-layer of two or more layers, if desired.
In the practice of the present invention, the transparent substrate is not specifically limited as long as it has enough of a self-supporting property to support the colored layer, but is preferably a plastic film. Suitable plastic film includes, for example, polyester film, polyethylene film, polycarbonate film, vinyl chloride film, acrylic film, polyurethane film, polyolefin film and vinylidene fluoride film, but is not limited thereto. The thickness of these films can vary widely according to use of the decorative film of the present invention, but is usually from about 30 to 150 xcexcm. Such a substrate is preferably transparent, but may also be semitransparent or slightly colored as far as it is desired and an adverse influence is not exerted on the effect of the present invention.
The colored layer provided on one surface of the transparent substrate is made of ink containing an optical coherent pigment capable of developing color by an interference action of light. The ink used herein is capable of printing by using a normal printing method such as screen printing method and gravure printing method. This printing may also be a single-color printing or a multi-color printing. The pigment capable of developing color by an interference action of light can afford a color developing effect peculiar to the pigment to ink, unlike ink with a normal solid color. Therefore, it is possible to remarkably improve the appearance and decorative effect of the decorative film obtained finally.
The ink constituting the colored layer is preferably polarizing pearl ink. The term xe2x80x9cpolarizing pearl inkxe2x80x9d used in the specification of the present application refers to an ink containing an optical coherent pigment having an operation/working-effect of changing the color and light according to a viewing angle as a result of interference between reflected light and transmitted light. The ink preferably contains a scaly mica pigment such as titanium dioxide-coated mica flake, iron oxide-coated mica flake and bismuth trichloride, and a scaly flake such as scaly glass. The size of these optical coherent pigments can vary within a wide range, but it is preferred that they usually have an average particle diameter ranging from about 5 to 130 xcexcm.
The amount of the pigment in the polarizing pearl ink can widely vary according to the desired color developing effect, but is generally preferred to be in the range of from greater than 1% by weight to less than 40% by weight, more preferably, within a range from about 3 to about 30% by weight. Most preferably, the content of the pigment is within a range from about 5 to about 15% by weight.
The film thickness of the colored layer can vary widely, but is preferably within a range from about 2 to about 20 xcexcm.
The clear layer to be provided on the outermost layer of the decorative film preferably has weathering resistance and heat resistance, in addition to the transparency per se as an essential property, from such a viewpoint that the clear layer is used as a protective film. Preferably, the clear layer can be formed by selecting a suitable resin from various resins satisfying the property. The clear layer preferably has good adhesion with the colored layer as a ground thereof. Suitable resin used for forming the clear layer includes, for example, polyester resin, polyethylene resin, polycarbonate resin, vinyl chloride resin, acrylic resin, polyurethane resin, polyolefin resin and vinylidene fluoride resin, but is not limited thereto. The film thickness of the clear layer can vary widely according to the desired effect, but is preferably within a range of from about 5 to about 100 xcexcm, and more preferably from about 20 to about 75 xcexcm. Furthermore, as the operation/working-effect of the addition of the clear layer, it can be expected to afford luster to the surface of the decorative film.
In the decorative film for glass-paned windows of the present invention, it is preferred to provide an adhesive layer on the lower surface of the substrate, which supports the film when applying to the glass-paned window, thereby to facilitate handling and application of the film. Suitable adhesive layer is an adhesive layer with a release liner. Such an adhesive layer is commercially available, easily. By using such an adhesive layer with a release liner in combination with the decorative film for glass-paned window of the present invention, the decorative film can be applied by the same operation as that in case of applying a general polarizing film and a scattering preventing film when the decorative film is applied to a glass-paned window of home and store and a glass-paned window of a private car.